Valve for rock drills



Nov. 29, 1932. I w, s 5 1,889,423

VALVE FOR ROCK DRILLS Filed June 6, 1951 IN VEN TOR.

116' 22221 J'milfi/J'a BY 5X44 1 M I}? 0 Z HIS ATTORNEY Patented Nov. 29, 1932 UNITED STATES PATENT OFFICE WILLIAM SMITH, SR, 01 EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-BAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY VALVE FOR ROCK DRILLS Application filed June 6;

This invention relates to rock drills,nbut more particularly to a distributing'valve for fluid actuated rock drills.

One object of the invention is toefiect a rapid distribution of pressure fluid to the cylinder of the rock drill and a consequent rapid reciprocation of the percussive element.

Another object is to assure a powerful 10 blow of the'percussive element against the working implement.

Other objects will be in part obvious and in part pointed out hereinafter In the drawing accompanying this specification and in which similar reference characters refer to similar parts,

Figure 1 is a longitudinal sectional elevation of a rock drill equipped with a valve constructed. in accordance with the practice of the invention and showing the'valve in position for admitting pressure fluid into the piston chamber to drive the piston on its working'stroke, and

Figure 2 is a similar view showing the valve in position to admit pressure fluid into the opposite end of the piston chamber for returning the piston. 7

Referring more particularly to the drawing, A designates generally so much of a rock drill as will serve to illustrate the invention and a practical application thereof. The rock drill A comprises a cylinder B having a piston chamber O therein to accommodate a reciprocatory hammer piston D of a conventional type having a head E and a forwardly extending reduced stem F. The head E of the piston D is guided by the piston chamber O in the usual manner and controls a free exhaust port G, and the stem F extends slidably through a closure H at the front end of the piston chamber O to deliver blows of impact to a working implement (not shown).

At the rear end of the piston chamber'O is an enlarged boreJ for the accommodation of valve mechanism, designated generally by K, and rotation mechanism which comprises the usual ratchet ring L and the head 0 of a rifle bar P. The rotation mechanism may be of conventional type in which the head 0 is 1931. Serial No. 542,514.

provided with the usual spring pressed pawls i chamber O and the ratchet ring Lforms a closure for the rear end of the piston cham her. It comprises a valve chest R having a valve chamber S therein to accommodate a distributing valve T. The valve chest R is in the form of a pair of plates U and V of which the plate U is disposed adjacent the piston chamber O and is provided at its rear end with an annular flange W into which extends a flange X of the plate V for centralizing the plates U and V with respect to each other.

Extending through the valve chamber S and forming an inner bounding surface therefor is a sleeve Y which extends with its ends'into the plates U and V and has a bore Z to form a bearing surface for the rifle bar P which extends therethrough. By fitting the ends of the sleeve Y snugly in the plates U and V leakage of pressure fluid from the valve chamber S into the rear end of the piston chamber O will be prevented. On the exterior of the sleeve Y is a rear ward reduced bearing surface I) for a bore 0 in the rear end of the valve T and a surface (1 :of enlarged diameter on the sleeve Y lying in the front end of the valve chamber S acts as a bearing surface for a bore 6 in the front end of the valve. V

The valve chamber S comprises rear and front reduced portions f and g respectively and an intermediate enlarged portion h. The rear reduced portion f accommodates the body portion j ofthevalve T and a flange k on the valve lies in the enlarged portion h of the valve chamber. On the front end of the valve is an annular extension 0 which is guided in the front reduced portion gv of the valve chamber. A vent 1) leads from the front end of the valve chamber to the atmosphere to subject the front end 9 of the annular extension 0 to atmospheric pressure. 7 The pressure fluid intended to be distributed by the valve T may be conveyed to the valve chamber, and more particularly to the enlarged portion h thereof, by a supply passage 1* in the ratchet ring L and the plate V, so that a constant supply of pressure fluid may be maintained in the enlarged portion h of the valve chamber.

The rear end of the flange it constitutes a pressure area 8 against which pressure fluid constantly acts tending to throw the valve T forwardly. At the rear end of the body portion j is an actuating surface 25 which is intermittently exposed to pressure fluid to augment the pressure acting against the actuating surface t for throwing the valve forwardly. Pressure fluid is conveyed to the actuating surface If by a kicker passage to leading from a point in the piston chamber G rearwardly of the exhaust port G to the rear end of the valve chamber S and being controlled by the head E of the piston D.

On the front end of the flange 7c of the valve is an actuating surface '0 which is intermittently exposed to compression from the rear end of the piston chamber C to throw the valve T rearwardly. The force of such compression is, however, augmented by the pressure fluid existing within a supply reservoir to in the valve T and which may be constantly admitted into the chamber IV through a port or ports a: in the body portion and being so located as to assure constant communication between the enlarged portion h of the valve chamber and the chamber or reservoir IV. The pressure fluid existing in the chamber w acts against a shoulder y at the juncture of the bearing portions 7) and d on the sleeve Y and a constant pressure area 2 on the valve T at the rear end of the reservoir w.

The pressure fluid utilized for driving the piston D forwardly flows over the periphery of the flange 7c and through a rear inlet passage or passages 2 in the plate U and openin into the rear end of the piston chamber The admission of pressure fluid to the front and of the piston chamber C is effected through a front inlet passage 3 which opens at one end into the front end of the piston chamber and with its other end into the rear reduced portion 7.

In the periphery of the body portion y of the valve is an annular groove 4: which, when the Valve is in the forward limiting position, establishes communication between the enlarged portion 71, and the inlet passage 8, and in the other extreme position establishes communication between the inlet passage 3 and a vent 5 leading from a point near the rear end of the reduced portion f of the valve chamber to the atmosphere.

In order to augment the compression in the rear end of the piston chamber C to expedite the building up of this force to a value capable of quickly and positively actuating the valve T rearwardly, the flange la is provided with a port or ports 6 which open into an annular groove 7 in the front end of the enlarged portion 72 of the valve chamber and communicating with the rear inlet passage.

The operation of the device is as follows: With the supply passage 1 open to a source of pressure fluid supply and the Valve in the rearward position illustrated in Figure 1, pressure fluid flows around the edge of the flange k, thence through the inlet passage or passages 2 into the rear end of the piston chamber to drive the piston D forwardly on its working stroke. During this admission of pressure fluid into the piston chamber the force or suction exerted on the edge of the flange k by the pressure fluid flowing thereover will be insufficient to disturb the position of the valve since, as will be observed, pressure fluid will then be acting against the front or actuating surface '0 of the flange 70. This force and the pressure acting against the constant pressure surface 2 will maintain the valve stationary in the rear end of the valve chamber.

As the piston D proceeds forwardly it will uncover the kicker passage u. In this way pressure fluid is admitted from the rear end of the piston chamber through the kicker passage a into the rear end of the valve chamber S to act against the actuating surface t.

The pressure fluid thus acting against the actuating surface t, together with that acting against the constant pressure area 8, will actuate the valve T forwardly where it will be held temporarily immovable by the pres sure acting against the pressure area 8. Immediately thereafter the head E of the piston D will uncover the exhaust port G. The pressure fluid in the rear end of the piston chamber C and that acting against the actuating surface t will then be exhausted to the atmosphere and at about the instant that the piston D delivers its blow against the working implement.

In the new position of the valve, pressure fluid flows from the enlarged portion h of the valve chamber through the annular groove 4-. in the body portion of the valve, thence through the front inlet passage 3 to the front end of the piston chamber C to actuate the piston D rearwardly. As the piston proceeds in this direction it will first cover the exhaust port G and immediately thereafter the kicker passage u. The air in the rear end of the piston chamber will then be compressed by the piston. This compression will be augmented by the pressure flowing through the ports 6 and the inlet passage 2 until the value of the pressure in the rear end of the piston chamber becomes high enough, so that, with the assistance of the pressure fluid acting against the pressure area 2, it will actuate the valve rearwardly against the pressure acting upon the pressure area s. The piston will then again be driven forwardly by the [FIG pressure fluid flowing into the rear end of the piston chamber. After the head E of the piston covers the exhaust port G the air compressed in the front end of the piston chamber will flow through the inlet passage 3, the annular groove 4: and through the passage or vent 5 to the atmosphere so that the piston D may deliver a heavy blow against the working implement.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, a valve chest having a supply passage and a valve chamber comprising an enlarged portion, inlet passages leading from the valve chamber to the cylinder, a distributing valve in the valve chamber having a pair of opposed differential pressure areas constantly exposed to pressure fluid, an actuating surface intermittently exposed to compression from the cylinder to augment the pressure fluid acting against the smaller pressure area for actuating the valve to one limiting position and being subjected to live pressure fluid to assist the pressure fluid acting against the smaller pressure area in holding the valve, a second actuating surface intermittently exposed to live pressure fluid to augment the pressure fluid acting against the larger pressure area for actuating the valve to another limiting position, and a flange on the valve lying in the enlarged portion and over which pressure fluid flows from the supply passage to both ends of the cylinder.

2. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, a valve chest having a supply passage and a valve chamber comprising an enlarged portion, inlet passages leading from the valve chamber to the cylinder, a hollow distributing valve in the valve chamber con stantly bearing interiorly and 'exteriorly at its extremities against the bounding surfaces of the valve chamber, a pair of opposed differential pressure areas constantly exposed to pressure fluid, an actuating surface intermittently exposed to compression from the cylinder to augment the pressure fluid acting against the smaller pressure area for actuating the valve to one limiting position and be ing subjected to live pressure fluid to assist the pressure fluid acting against thesmaller pressure area in holding the valve, a second actuating surface intermittently exposed to K live pressure fluid to augment the pressure acting against the larger pressure area for actuating the valve to another limiting position, and a flange on the valve lying inthe enlarged portion and over which pressure fluid flows from the supply passage to both ends of the cylinder. 1

3. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, a valve chest having a supply passage and a valve chamber comprising an enlarged portion, inlet, passages leading from the valve chamber to the cylinder, a'hollow against the smaller pressure area for actuating the valve to one limiting position and being subjectedto live pressure fluid to assist the pressure fluid acting against the smaller pressure area in holding the valve, a second actuating surface intermittently exposed to live pressure fluid valved by the piston to augment the pressure acting against the larg? er pressure area for actuating the valve to another limiting position, and'a flange on the valve lying in the enlarged portion and over Which pressure fluid flows from the supply passage to both ends of the cylinder.

4. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, a valve chest having a supply passage and a valve chamber comprising an enlarged portion and a reduced portion, front and rear inlet passages leading from the valve 7 chamber to the cylinder, a valve in the valve chamber having a body portion slidable in the reduced portion, a flange on the valve lying in the enlarged portion and being of smaller diameter than the said enlarged portion, a supply reservoir in the valve in constant communication with the supply passage, a pressure area on the rearend of the flange constantly exposed to pressure fluid tending to shift the valve for communicating the front inlet passage with'the supply passage, an actuating surface on the rear end of the body portion intermittently exposed to pressure fluid valved by the piston to augment the pressure acting against the pressure area, an actuating surface on the front end of the flange subjected to compression from the rear end of the cylinder to shift the valve for communicating the rear inlet passage with the supply passage, and a pressure area at the rear end of the reservoir constantly exposed to the pressure fluid therein to augment the compression acting against the second mentioned actuating surface.

5. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, a valve chest having a supply passage and a valve chamber comprising an enlarged portion and front and rear reduced portions, a vent leading from the front reduced portion to the atmosphere, front and rear inlet passages leading from the valve chamber'to the cylinder, a valve in the valve chamber having a body portion slidable in the rear reduced portion, a flange on the valve being of smaller diameter than the enlarged portion and lying therein, an annular extension on the valve slidable in the front reduced portion, a supply reservoir in the valve in constant communication with the supply passage, a pressure area on the rear end of the flange constantly exposed to pressure fluid tending to shift the valve for opening the front inlet passage, an actuating surface on the valve intermittently exposed to pressure fluid valved by the piston to augment the pressure acting against the pressure area, an actuating surface on the front end of the flange subjected to compression for shifting the valve to open the rear inlet passage, a pressure area at the rear end of the reservoir of smaller area than the first said pressure area and being constantly subjected to pressure fluid in the reservoir for augmenting the compression acting against the second mentioned actuating surface, and a leak port in the valve to constantly admit pressure fluid into the rear end of the cylinder.

In testimony whereof I have signed this specification.

lVILLIAM A. SMITH, SR. 

